1. Field of the Invention
The present invention relates generally to method and apparatus for maintaining and servicing a pressurized system such as a refrigeration system or the like, and more particularly, but not by way of limitation, to method and apparatus for removing and replacing a closure member in a pressurized refrigeration system without depressurizing the system.
2. Description of the Prior Art
The prior art contains a number of teachings of servicing tools which provide access to a refrigeration system or the like to evacuate or charge the system. One such tool is disclosed in U.S. Pat. No. 3,299,648, issued to White, et al.
It should be noted, that neither the White tool nor any other known tools permit the removal and replacement of the threaded closure member in a pressurized refrigeration system without depressurizing the system.
It has become common practice in the refrigeration industry to provide access to pressurized refrigeration systems through threaded fittings in which a threaded check valve core is installed. Such threaded check valves are of the type commonly used in automobile tire valve stems and are often referred to as Schrader-type valve cores.
It has been found that the Schrader-type valve cores used in refrigeration systems are not subject to extremely high quality control measures. Approximately 50 percent of the valve cores initially installed in a refrigeration system are found to be incapable of holding the proper operating pressure to permit efficient operation of the refrigeration system. It is, therefore, necessary many times to replace an unsatisfactory valve core after charging a refrigeration system with refrigerant. It is to this industry-wide problem that the method and apparatus of the present invention is directed.